Emulsion testing



May 18, 1954 .1. F. CHITTUM 2,678,911

EMULSION TESTING Filed Oct. 25, 1950 3 Sheets -Sheeft l l l l l l l l l INVENTOR Joseph F. Chirfurp May 18, 1954 J. c -nTu 2,678,911

EMULSION TESTING Filed Oct. 25, 1950 3 Sheets-Sheet 2 f" /39v 1] /38 l 25 i on.

30 I EMULSION WATER INVENTOR Joseph F. ChiHum FIG. 4

May 18, 1954 Filed Oct. 25 1950 J. F CHITTUNI 2,678,911

EMULSION TESTING 3 Sheets-Sheet 3 I I I I I I /75 F IG. 7

INVENTOR 75 75 Joseph F.ChiHum Patented May 18, 1954 UNITED STATES ZPATENT OFF ITCE EMULSION TESTING "Joseph F; .Ghittum, Whittier, ;0alif., assignor to California Research Corporation, .San Francisco, Califl, a corporation of Delaware Application October 25, 1950, SerialNo. 192,015

sions of varying types and characteristics, each requiring a'different'chemical reagent. As distinguished from'these prior theories :of waterin-oil emulsions, I have found that stable emulsions in which water is the dispersed constituent are in generalof only two types. These are classifiable as either positive or negative depending upon whether theelectrical charge cnthe surface of the dispersed. droplets is positive or negative, while the opposite charge is in the continuous phase. In this type of emulsiomwater is the dispersed phase and oilis the continuous phase in the emulsions being tested, and Ihave found that an electrical double layer isestablished in the oil-side of theinterface. accomplished by the accumulation of oil-soluble or dispersable ions near the boundary between the phases with the occurrence of associated ions of opposite charge on the boundary itself.

Accordingly, I have found that in order either to break an emulsion or to form an emulsion of this type, the nature, or sign, of the :electrical charge on the water phase determines the steps to be taken in either balancing or unbalancing the ionic charge surrounding the dispersed par- I ticles. By so determining the charge on athe water phase, the selection of chemical reagents which may be most useful in forming an emul sion, or those which may best be used: in breaking an emulsion, canbe more easilyzpredicted than has been possible heretofore.

It is therefore an object of the present invention to provide a method of testing the electrical polarity of the dispersed aqueous phase of a water-in-oil type emulsion by applying a directionalized potential betweena pair ofelectrodes, at least one of which is capable of releasinggas when contacted by water to determinethe ionic charge on the dispersed phase. a

It is a further object of the invention to provide a method for rapidly and accuratelydetermining thesign of the electrical charge 'on the water phase of an emulsion by measurement of the rate of hydrogen evolution from a water- -reactive metal-electrode to which a polarized This is 'stitutingthe aqueous :phase,then applying a current is appliedtodetermine the chemical reagents to employ either in forming or breaking such an'emulsion.

Still further objects and advantages of the present invention will become'apparent from" the following detailed descriptiontaken'in conjunction with'the' appendeddrawings which form an integral part of the specification.

Broadly, the inventionrrelates to a method of determining the electrical polarity of'the water or aqueousphase of ranremulsion of the water- "in-oil type which'comprises the. steps of contacting theemulsion withapair of electrodes at least one ofwhich. is .characterizedby its ability to liberate gaswhen' in'contact-with the water convoltage between said "pair -of -telectrodes and measuring the rate ofsevolution of: gas from said electrodes.

In the. drawings:

Fig. 1 is a schematic"representation of a preferred embodiment oft-apparatus which -may be used in carrying out the methodxoffthe-present invention.

Fig. 2 is a cross-sectional view of the emulsion testing aparatus shown:inFig. 1.

Fig. is a bottom view of the apparatus shown Figs. 1- and"2.

Fig. l -iszaschematic :representation of. an alternative formofapparatus .for carrying out the -metho'd--o'fthe presentinventionby which the -'emulsion may be'tested; in fsitu.

"Fig.5 is:aschematic"representation of still a further form of apparatus which may be used in testingthe electrical .polarity of theaqueous phase of an emulsion ofthe water-in-oil type.

Fig. 6 is a:schematicrepresentation of an alternativeform of apparatussimilar to that shown in' Fig. 4; useful in the present method of'testing emulsions.

Fig. '7 is a schematic representation of a further embodiment OCPfiIJDdlfltllSqllSGflll in carrying out the method-of'thepresentinvention for testing the electrical: charge .onithe aqueous phase of a water-in-oil emulsion.

Referring now to the 'drawings, and in par- 'ticular to Fig. 1 whereinthe preferred embodiment of' apparatus for carrying out themethod of the present invention is shown, it will be noted that a chamber: or body it], which may be of a generally cylindrical form, is provided with a ipairof upwardly extending cylindrical chambers "or tubes Hand l2. The .uper ends l3. and M, of tubes II and 12, respectively, are preferably sealed over, whilethe-opposite or lower ends of tubes H and I2 are open to chamber it. As best seen in Fig. 3, a dividing member or partition wall I5 is so positioned in chamber it] that the path between the open ends of tubes i l and i2 is through the open space i6 between partition and the plane of the base of chamber I 0. As shown in Fig. 2, a pair of electrical contact pins I! and it] are arranged to pass through the wall 19 of chamber ill. Pins 1! and I8 are preferably provided with a pin-like end 20 which is capable of impaling an electrode of relatively soft metal such as alkali metals, alkaline earth metals or amalgams or alloys of such metals. As shown in Fig. 1, such metals may thus be positioned on contact pins i1 and It to provide a pair of metallic electrodes 2! and 22.

In the assembly of the equipment described hereinbefore, for the purpose of testing an emulsion for the electrical polarity of the dispersed aqueous phase, the chamber H! is inverted so that tubes I i and 52, as well as chamber iii, may be filled with the emulsion to be tested. Chamber It] is preferably completely filled and a watch glass, or base member, 23 positioned to retain the emulsion within the test apparatus. The entire assembly of base member 23 and chamber 8 with metallic electrodes 2| and 22 positioned as shown is then inverted to the position shown in Fig. 1. Under this condition, it will be apparent that electrodes 2| and 22, which may be selected from the materials enumerated above, for example sodium, are free to react with the water in the emulsion to liberate hydrogen gas from the water of the emulsion. This reaction occurs as fast as water droplets diffuse to the reactive metal surface. Such gas will of course rise, respectively, from electrodes 2% and 22 into tubes H and I2 and collect adjacent the closed ends l3 and M of the tubes. However, as in the present arrangement, where the electrodes are of substantially the same size and material, the rate of evolution of gas will be substantially the same in both tubes.

I have found that by the application of a directionalized or polarized electrical voltage between electrodes 2! and 22, for example, by means of a battery 24 which may be connected through a switch 25 to electrical contact pins I? and i8, that it is possible to obtain a difference in the rate of evolution of gas from elcctrodes 2| and 22, depending upon the direction of the voltage applied from battery 24. This is because opposite charges on the emulsion droplets and one metal electrode will result in attrac tion and consequent increased reaction at one ofthe electrodes. Like charges on the water droplets and the other metal electrode will result in repulsion and consequent decreased reaction between that electrode and the water droplets.

For the purpose of reversing the polarity of voltage between electrodes 2| and 22, switch 25 is preferably of 'the-double-pole, double-throw type. As seen in Fig. 1, the rate of evolution of gas due to the reaction of the metal of the electrode 22 and the water droplets of the emulsion has been greater than the rate due to reaction of electrode 2! and the water droplets. This is evidenced by the fact that a greater amount of gas collected in tube 12 than in tube H. Since the polarity of the applied voltage from battery 24 is known by the connection through switch 25, the charge on the suspended or dispersed aqueous particles in the emulsion under test may be readily determined. If on the other hand electrode 22 had been connected to the opposite side of battery 25, it will be apparent that the charge on the water droplets was of the reverse sign. Accordingly, it is apparent that the purpose of the reversing switch 25 is to provide a positive check of the ionic charge on the dispersed particles by permitting a reversal of the electrical potential between electrodes 2! and By operation of reversing switch 25, it will be appreciated that the rate of evolution of hydrogen gas under the sa e conditions enumerated above would increase in tube ll, while the rate of evolution from electrode 22 into tube i2 would decrease. In this way, it is possible to obtain a confirmation of the results of the previous test.

Referring now to Fig. i in which there is shown an alternative embodiment of apparatus which may be employed in carrying out the method of the present invention, it will be noted that this apparatus provides means for testing an emulsion such as that produced from an oil well, to determine the electrical charge on the dispersed phase without removing a sample of the emulsion from the usual storage tank. As diagrammatically illustrated, the emulsion 26 may be due to the inter-mixing of an overlying oil 2'! and the underlying water 28 in a tank 29. In order to test emulsion 26 in situ in tank 29, a pair of elongated tubes 30 and 3!, preferably constructed of glass, quartz or plastic, are adapted to be lowered into tank 29 so that the lower ends 32 and 33 are open to emulsion 25. Within the lower ends of tubes 39 and 3 I, the alkaline earth metal, alkali metals as well as amalgams and alloys of these metals, may be employed as electrodes 34 and 35. Electrodes 34 and 35 may be connected to a source of D. C. potential, such as battery 24 described in the previous embodiment, through double-pole, double-throw switch 25 and lines 35 and Si, which respectively are connected to electrodes 3- 1 and 35. The operation of the electrodes 35 and 35 within tubes 30 and Si is very similar to that described in connection with the previous embodiment. However, in order to fill tubes 39 and 3! with emulsion 26, a pump 38 is connected to an intake line 38 connected in common to the tops of tubes 30 and 3| through valves 43 and M, respectively. In order to prevent the inter-mixing of excess emulsion drawn up through tubes 3% and 3! with the overlying oil 21, a return line 42 may be provided between pump 38 and emulsion strata 26.

The operation of the embodiment scribed includes the steps of pumping emulsion 26 into tubes 3!) and 3! so that they are substantially filled. This may be accomplished by the opening of valves 45 and M and driving pump 36 by any conventional means until the emulsion is returned through line 42 to the strata of emulsion in tank 29. Then, valves 4B and H may be closed and with the D. C. potential applied from battery 24, the rate of evolution of gas may be measured in the graduated portions 63 and M of tubes 39 and 3!. The applied voltage through emulsion 26 will of course be between electrodes 35 and 35. For purposes of checking the results of this test obtained with battery 24 connected to electrodes 3 and 35, the direction of the applied voltage may be reversed by double-pole, double-throw switch 25 for the purpose described in connection with the operation of the embodi ment shown in Fig. 1.

Referring now to the apparatus shown in Fig. 5 which may be used in the practice of the method of the present invention, I have provided an elongated chamber, or tube, preferably formed just deing material. Tube is-provi'ded with an elongated, reduced portion "54 having a -graduated scale adjacent the upperend of portion- 54. For

the purpose of filling tube =50 prior 'tothe testing of the emulsion; an integral stop-cockarrange- "ment 55 and a funneltiare'arranged above portion. It will'be apparent that the emulsion to betested maybe poured intofunnel 55 and the stop-cock'55-turne'd to an open position" to permit" the tube 5Iltobe completely filled with the emulsion" under test. A gas-generating elec- "trode 51, selected from *the group of metals capable of generating gas in the presence of water; is preferably positioned adjacent the lower end of enlarged portion by any suitable means,

such as a pairof support pins58. "Electrode ii! is connected to a current.sourcebymeans of line 59 which is arranged to pass through a 'sealed, lead-in portion at in tapered portion fii between the upper and lower portions of tube 5%. In order to provide the opposite electrode to establish a potential across'the emulsion invessel 53, a band, or circular ringiiZ' of any cenductive 1 metal is 4 preferably positioned adjacent the inner, side wall of vessel 53 and connected through a contact pin63 to electrical line ii l. Conductor lines 59 and-64 are then connected through switch 25 to a pulsating D. C. source provided by a half-wave rectifier 65 "connected "to an A.- C. supply line.

In 'the operation ofthe apparatus shown in Fig. 5, it will beapparentthatthe vessel 53 is filled with the emulsion-to be tested to a suflicient depth so-that band electrode BZ is incontacting relationship to the emulsion and tube 58 completely filled with the emulsion under test through funnel 56 and stop-cock 55. As described above, the lowerportionBl of tube 50 is positioned above the base of vessel 53=by-means of supports 52 so that afree electrical path may 1 be provided between the gasgenerating electrode 51 and ring electrode 62. While in the present embodiment it will be apparentthat gas evolved from the emulsion is collected only from above electrode 51, it has been found desirable to provide ,a reversingelectrode by areversing switch such'as switch 25 to-slow-down intermittently the reaction of electrode 51 with: the water in the emull'li attached to thelowerend-oi tube". The purpose of flare 16 is to prevent the escaperoi gas bubbles-exceptinto tube 10 duringthetesting of the emulsion. "Since tube 10 is constructed of a conducting metaL-asight glass arrangement is'provided by means of an elongated slot'll cut in the opposite 'wallsof tube-l0. Preferably this slot comprisesa pair of openings positioned l apart in the circumference of the cylindrical tube 10, so 1 that light may pass directly through the opposed openings'll. In'order to maintain the tube '70 closed'to the atmosphere, the'slots 11 are provided withglass-wiridows 137 having'gradl5 uate marks thereon to permit the observation of the rate of gas evolution from. electrode 14. For a purpose similar to that in the apparatus shown in Fig. 4,I"have provided a pump "19 and a valve 80 in -a draw-up line-Bl. By this arrangement pump 19 is aidaptedto draw emulsion into tube H1 and completely fill thetube when valve 180 is open. Then, valve Bilmaybe hlosedaarid the rate of evolution or gas fromelectrode 14 measured by observing the downward movement 101 the emulsion level as indicated through "slots "11 and w-indowsTB in tube 70. In the present'embodiment the electrical circuit is provided by battery 24, reversing'switch 25 andlinesi iizrand 83 which are respectively connected to electrode '14 and the wall of tube'lll. Asmentioned above,

the wall of tube '10 in this arrangement is formed of an electrically conductingmaterialso that line83 may-be directly attached to thertubing adjacent upper end '13. It will of coursebe 'apparent that line 82 may either-be insulated or passed through-an insulating bushing 84 in end wall 13 andthen downwardly throughthe sion. This may be found particularly desirable where the water droplets compriseja higher percentage of the emulsion and electrode 51 is a particularly active metal, such as potassium or sodium.

In Fig. 6 there is shown a further alternative arrangement for testing the electrical charge on the dispersed particles in an emulsion which may be utilized in a location such as that contemplated for the apparatus shown in Fig. 4, i. e., emulsion in situ. However, in the present embodiment the gas-collecting cylinder or chamber designated generally as 'H) is preferably constructed of a conducting material such as copper, brass or bronze, and is adapted to be lowered into a tank containing the emulsion to be tested by means of a bail H and chain 72 which are connected to the closed and i3 of cylinder, or tube, 10. In this arrangement a gas evolving electrode 14 is positioned below the inner end of tube 10 by a pair of insulating pins 15 which are in turn attached to a flare, or skirt, portion center of tube 10 to make electrical contact'with electrode 14. As distinguished from the arrangement in 'Fig. 4, any :excess emulsion ."drawn through line 8| maybe collected from outlet 'line Errand-suitably disposed of.

Referring now to the apparatus shown in Fig. 7, a metallic testing vessel 90, which is adapted'to be directly connected to a source of D. C supply,

such as D. C. generator-"9|, provides one roi the electrodes of "the emulsion testing apparatus.

Vessel Bil-additionally provides a support for a pair of non-conducting" tubes 92 closed at their upper ends in the same manner as tubes I l and -lzin Fig. 1. Asupporting arrangementfor: tube 92 isprovidcd byfour support wires93 adapted to -rest on the top of the side wall of vessel .90.

Wires 93 in turn suspend a clamping platform'94 adapted to engage the outer walls oi'tubes 92.

Tubes 92-are=so positioned between the clamping mea-ns 94thatthe'lowerends of the tubes are supported abovethe-base of vessel-50. For'the =purpose explained in regard to the foregoing embodiments, gas evolving electrodes 95 are positioned adjacent the lower ends of tubes 92 by any suitable means such as pins 95 and the electrodes 95 connected in common to a D. C. generator 9| through reversing switch 25 and lines 91 and 98. For the purpose of preventing the lead-in wire 91, which is connected into both tubes 92, from interfering with the measurement of gas evolved in the upper ends of the tubes, a lead-in bushing 99 is preferably provided in each of the side walls of tubes 92 for admitting line 91 to the interior thereof. Wire 98 is connected to the metallic side wall of vessel to provide the electrically conductive circuit through the emulsion contained therein. The purpose of the present embodiment is to provide a parallel arrangement for measuring the rate of evolution of gas from the water phase of an emulsion containing water in order to permit the concurrent use of different materials in electrodes 95.

In the operation of the apparatus shown in Fig. '7, it will be apparent that the emulsion to be tested is filled into vessel 90 and the tubes 92 inverted while clamped together by clamping means 94 and then returned to the position shown in Fig. '7 so that the electrical circuit may be completed between the inner surface of vessel 90 and the gas evolving electrodes 95.

From the description of the foregoing embodiments of apparatus which may be utilized in carrying out the method of the present invention, it will be apparent that numerous changes and modifications in the apparatus may be made depending upon the conditions, locations and availability of the emulsions to be tested, without departing from the method of the present invention. Likewise, it will be apparent that the exact electrode material will be selected depending primarily on the percentage of water content of the emulsion under test. In this regard, it will be apparent that sodium and potassium are extremely satisfactory for testing water-in-oil types of emulsion where the percentage of water is extremely small, whereas in an emulsion containing a higher percentage of water the use of an analgam such as mercury and sodium, or mercury and potassium, is more desirable. Additionally, it will be apparent that the applied voltage from the steady or pulsating D. C. source will be varied in accordance with the conductivity of the emulsion. In particular, a D. C. voltage of 500 to about 750 volts has been found desirable for a rapid test of most emulsions of the waterin-oil type.

From the foregoing description of the method of the present invention, it will be apparent that a method of testing the electrical polarity of an aqueous emulsion to determine the ionic charge on the dispersed phase ha been provided which may be accurately and rapidly carried out. Additionally, the present method provides a means for rapidly determining the effectiveness of chemical reagents for both breaking and forming emulsions of the water-in-oil type.

While modifications and changes in the method and apparatus described in this specification will occur to those skilled in the art, all such modifications and changes that fall within the scope of the appended claims are intended to be included thereby.

I claim:

1. A method of determining the electrical polarity of the aqueous phase of a water-in-oil typeemulsion comprising the steps of contacting said emulsion with a pair of electrodes, at least one of which is characterized by its ability to liberate gas when in contact with said aqueous phase, applyin a polarized voltage between said pair of electrodes and measuring the evolution of gas from the aqueous phase of said emulsion in contact with said one electrode.

2. A method of determining the electrical p0- larity of the water droplets dispersed as a waterin-oil emulsion comprising the steps of contacting said emulsion with a pair of electrodes at least one of which is characterized by its ability to liberate gas when in contact with said water droplets, applying a polarized voltage between said one electrode and the other electrode and measuring the evolution of gas from the water droplets which contact said one electrode.

3. A method of testing an emulsion of the water-in-oil type comprising the steps of positioning a pair of substantially similar metal electrode in said emulsion, said electrodes being characterized by their ability to liberate hydrogen when chemically reacted with water and selected from the group consisting of alkali metals, alkaline earth metals and alloys containing said metals as an active hydrogen-liberating agent therein, applying a directionalized current between said electrodes and separately measuring the rat of evolution of hydrogen from emulsion surrounding said electrodes as an indication of the sign of the electrical charge on the Water particle in said emulsion.

4. A method of determining the electrical polarity of water droplets dispersed as a water-inoil emulsion comprising the steps of contacting said emulsion with a pair of electrodes selected from the group consisting of alkali metals, alkaline earth metals, and alloys of alkali and alkalin earth metals, passing a direct current between said electrodes and measuring the rate of gas evolution from said emulsion around each of said electrodes as an indication of the polarity of said water droplets.

5. A method in accordance with claim 4 in which said electrodes are sodium.

6. A method in accordance with claim 4 in which said electrodes are potassium.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,116,509 Cottrell May 10, 1938 OTHER REFERENCES Journal of Industrial And Engineering Chemistry, vol. 12 (1920) pages 133-135.

Treatise On Inorganic And Theoretical Chemistry, by Mellor, vol. 1, (1922), page 135. 

1. A METHOD OF DETERMINING THE ELECTRICAL POLARITY OF THE AQUEOUS PHASE OF A WATER-IN-OIL TYPE EMULSION COMPRISING THE STEPS OF CONTACTING SAID EMULSION WITH A PAIR OF ELECTRODES, AT LEAST ONE WHICH IS CHARACTERIZED BY ITS ABILITY TO LIBERATE GAS WHEN IN CONTACT WITH SAID AQUEOUS PHASE, APPLYING A POLARIZED VOLTAGE BETWEEN SAID PAIR OF ELECTRODES AND MEASURING THE EVOLUTION OF GAS FROM THE AQUEOUS PHASE OF SAID EMULSION IN CONTACT WITH SAID ONE ELECTRODE. 